Memory for emotionally arousing events over time in Autism Spectrum Disorder

Emotionally arousing events are typically better remembered and more resistant to forgetting than neutral events. Findings from word list paradigms suggest that this may not hold for individuals with Autism Spectrum Disorder (ASD), who also tend to be less accurate as eyewitnesses under some circumstances. To test whether attenuated effects of arousal on memory may be responsible for poorer eyewitness testimonies in ASD, we asked adults with and without the disorder to view either arousing or neutral versions of a narrated slide sequence (Experiment 1) or video clip (Experiment 2) before assessing their memory for the material. Both groups exhibited increases in psychophysiological arousal during the arousing compared with the neutral version of the narratives, and both groups also demonstrated a memory advantage for the arousing events. Contrary to predictions, these observations indicate that stimulus induced arousal modulates memory for naturalistic events relatively typically in ASD. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Memory for traumatic events

This research compares memory for traumatic events with memory for non-traumatic versions of the same event. In Experiment 1, subjects watched an event depicted in slides while focusing and rehearsing the central detail of each slide. They were tested after a short or a longer retention interval (20 min or 2 weeks). Subjects who watched the traumatic version were better able to recall the central details that they had rehearsed, but were less well able to recognize the specific slides that they saw. Better recall for the traumatic group did not occur because the words used to describe the recalled details were inherently more memorable, as shown in Experiment 2. In Experiment 3, subjects watched either a traumatic or non-traumatic version of a filmed event and about 6 months later they were asked to remember the essence of the film. Subjects who saw the traumatic version were better able to recall the essence of the film. A similar finding was obtained with a group of subjects from Experiment 1 who were also contacted about 6 months after their initial participation. These results suggest that some information (the essence, the theme) of a traumatic event might be relatively well retained in memory, while memory is impaired for many of the specific, and especially peripheral, details.     

Memory for time and place contributes to enhanced confidence in memories for emotional events

Emotion strengthens the subjective sense of remembering. However, these confidently remembered emotional memories have not been found be more accurate for some types of contextual details. We investigated whether the subjective sense of recollecting negative stimuli is coupled with enhanced memory accuracy for three specific types of central contextual details using the remember/know paradigm and confidence ratings. Our results indicate that the subjective sense of remembering is indeed coupled with better recollection of spatial location and temporal context, but not higher memory accuracy for colored dots placed in the conceptual center of negative and neutral scenes. These findings show that the enhanced subjective recollective experience for negative stimuli reliably indicates objective recollection for spatial location and temporal context, but not for other types of details, whereas for neutral stimuli, the subjective sense of remembering is coupled with all the types of details assessed. Translating this finding to flashbulb memories, we found that, over time, more participants correctly remembered the location where they learned about the terrorist attacks on 9/11 than any other canonical feature. Likewise, participants' confidence was higher in their memory for location versus other canonical features. These findings indicate that the strong recollective experience of a negative event corresponds to an accurate memory for some kinds of contextual details but not for other kinds. This discrepancy provides further evidence that the subjective sense of remembering negative events is driven by a different mechanism than the subjective sense of remembering neutral events.     

Memory for thematically arousing events

Many studies have indicated that emotional arousal improves memory for the center, or gist, of an event but undermines memory for the event's periphery. However, all of these studies have elicited emotion by showing participants some salient visual stimulus intended to arouse them (e.g., the sight of a wound). This stimulus may have served as an attention magnet, and this, not the arousal, may have been the cause of the observed narrowing of memory. In this article, we examine how participants remember events that involve thematically induced arousal, arousal produced by empathy, rather than by a visual emotional stimulus. The data show that emotionality improves memory for all aspects of these events, with no memory narrowing.     

Memory for unique personal events: The roommate study

Memory for naturally occurring episodic events was measured along with memory for the date of occurrence of those events. The effect of rehearsal was also measured. Participants in the experiment recorded unique personal events for themselves and their roommates for a semester (data were collected for approximately 14 weeks). They also rated the memorability of the events at the time the events were recorded. The roommates were unaware that they were to be tested on the events until approximately I week before the memory test. Accuracy in dating events decreased at the rate of roughly 1 day every week of the retention interval. Events rated as memorable were encoded better than events rated as unmemorable but were forgotten at the same rate. Increasing rehearsal decreased the rate of forgetting the events. Although the recorders selected the events to be recorded and knew they were to be tested on those events, they did not differ from their roommates on any of the memory measures     

Memory for unique personal events: Effects of pleasantness

College students recorded unique personal events for a 3-month period. At the time of recording, they rated the pleasantness or unpleasantness of the event. Subsequent memory ratings showed no effect of type of affect (i.e., pleasant vs. unpleasant events) but a strong influence of intensity of affect. In contrast, the data for estimating the date of occurrence of events showed an effect of type of affect, with pleasant events estimated more accurately than unpleasant events. A detailed analysis of the data indicated that the effect could not be attributed to the predictability of pleasant events. A red-letter day effect was proposed as an explanation for the estimation data.     

Memory for unattended events: Remembering with and without awareness

The effects of memory for unattended events—for example, events that occur while a person is asleep, anesthetized, or selectively attending to other ongoing events, as in a speech-shadowing task—are rarely revealed in tests of retention that require remembering to be deliberate or intentional. Might such effects become evident in tests that do not demand awareness of remembering? Results of the present shadowing study, involving the recognition and spelling of previously unattended homophones, suggest an affirmative answer to this question.     

Memory conjunction errors for autobiographical events: more than just familiarity

Two diary studies investigated the prevalence of memory conjunction errors for real-life events. In both studies, participants completed detailed diary pages over the course of several weeks. Participants in both diary studies committed memory conjunction errors on a later recognition memory test. In the second diary study participants also made remember/know judgements. For a large proportion of their memory conjunction errors participants indicated that they "remembered" the event occurring in that context. These diary studies demonstrate that memory conjunction errors do occur for autobiographical memories, and these errors can seem compelling.     

Memory for action events in the bottlenosed dolphin

We investigated whether a bottlenosed dolphin’s ability to recall and repeat actions on command would immediately generalize to actions performed with specified objects. The dolphin was tested on her ability to repeat 18 novel behaviors performed with potentially interchangeable objects specified using an artificial gestural language. Such “action events” were correctly repeated at above chance levels, indicating that the dolphin had access to memories of those events. Performance levels were, however, lower than in previous tests. The dolphin appeared to have difficulty recalling which object an action was performed with. Previous research has demonstrated that animals can recall features of their environment and features of their actions independently of one another. The results of this study demonstrate (1) that the dolphin’s concept of repeating extends beyond simply accessing memories of movement patterns, and (2) that dolphins’ memories of past events incorporate representations of both self-performed acts and objects, locations, or gestural instructions. Received:10 October 1998 / Accepted after revision: 22 December 1998     

Memory and time

The purpose of this essay is to clarify the notion of mnemonic content. Memories have content. However, it is not clear whether memories are about past events in the world, past states of our own minds, or some combination of those two elements. I suggest that any proposal about mnemonic content should help us understand why events are presented to us in memory as being in the past. I discuss three proposals about mnemonic content and, eventually, I put forward a positive view. According to this view, when a subject seems to remember a certain event, that event is presented to her as making true a perceptual experience that caused the very memory experience that she is having.

Memory aids people use: Two interview studies

In two interview studies subjects were asked what memory aids they used and how often. In particular, the reported frequencies of use of external aids such as shopping lists and memos were compared with those of internal aids that have been investigated by psychologists, such as the method of loci. Subjects in the first study were 15 male and 15 female university students, and in the second, a group of 30 adult women, most of whom were housewives. In both studies the aids reported to be used most were external ones. However, it is pointed out that the most commonly used methods of remembering must be internal, although these are not usually considered to be aids. Some difficulties that arise in the assessment of memory in interview and questionnaire studies are discussed.     

Memory for lists of spatial events in the rat

Three experiments are reported in which rats were presented with lists of spatial events or responses in distinct visual contexts, and retention subsequently was measured for the events occuring at each serial position. In Experiments 1 and 2, lists contained different numbers of forced choices on successively presented T-mazes, and memory for each serial position was tested on each trial. In Experiment 3, lists were made up of different numbers of forced entries into randomly ordered arms on the eight-arm radial maze, and memory for one serial position was probed on each trial. All three experiments yielded serial position curves which demonstrated recency effects but no primacy effects. Comparisons of retention for different list lengths within each experiment indicated that retention of shorter lists was equivalent to retention of the final items of longer lists and superior to retention of the initial items on longer lists. This pattern of results indicated that there was no evidence of proactive inhibition in the serial position curves. Analysis of input and output interference effects and the results of control tests suggested that both retroactive inhibition and time-based forgetting processes were responsible for recency effects.     

Memory for people and their actions: further evidence for an age-related associative deficit

The associative deficit hypothesis (M. Naveh-Benjamin, 2000) attributes age-related memory deficits to the inability to encode and retrieve bound units of information. The present experiment extended this deficit to a new form of stimuli, dynamic displays of people and their performance of everyday actions. Older and younger adults viewed a series of brief video clips, each showing a different person performing a different action, and were tested over memory for individual people, individual actions, and the person-action combinations. Older adults did exhibit an associative deficit, and this was related to an increased proportion of false alarms on the associative test.     

Memory for details about people: familiarity,relatedness, and gender congruency

This study examines factors that influence memory for details about people. In two experiments, subjects learned fictitious details about familiar (friends, relatives) and/or unfamiliar individuals, and were tested both immediately and after a 1-week delay. To control for a confounding between familiarity and genetic relatedness in Experiment 1, in Experiment 2 specific relationships (identical twin, first cousin, acquaintance) were assigned to unfamiliar individuals. Across experiments, retention was enhanced for familiar compared to unfamiliar individuals, for friends/acquaintances compared to relatives, for more closely than distantly related individuals, and for individuals of the opposite gender as the subject.     

A diary after dinner: How the time of event recording influences later accessibility of diary events

Recording the events of a day in a diary may help improve their later accessibility. An interesting question is whether improvements in long-term accessibility will be greater if the diary is completed at the end of the day, or after a period of sleep, the following morning. We investigated this question using an internet-based diary method. On each of five days, participants (n?=?109) recorded autobiographical memories for that day or for the previous day. Recording took place either in the morning or in the evening. Following a 30-day retention interval, the diary events were free recalled. We found that participants who recorded their memories in the evening before sleep had best memory performance. These results suggest that the time of reactivation and recording of recent autobiographical events has a significant effect on the later accessibility of those diary events. We discuss our results in the light of related findings that show a beneficial effect of reduced interference during sleep on memory consolidation and reconsolidation.